The increased number of cancer cases reported in the United States, and, indeed, around the world, is a major concern. Currently there are only a handful of detection and treatment methods available for some specific types of cancer, and these provide no absolute guarantee of success. In order to be most effective, these treatments require not only an early detection of the malignancy, but a reliable assessment of the severity of the malignancy.
Cancers can be viewed as a breakdown in the communication between tumor cells and their environment, including their normal neighboring cells. Growth-stimulatory and growth-inhibitory signals are routinely exchanged between cells within a tissue. Normally, cells do not divide in the absence of stimulatory signals or in the presence of inhibitory signals. In a cancerous or neoplastic state, a cell acquires the ability to “override” these signals and to proliferate under conditions in which a normal cell would not.
In general, cancerous cells must acquire a number of distinct aberrant traits in order to proliferate in an abnormal manner. Reflecting this requirement is the fact that the genomes of certain well-studied tumors carry several different independently altered genes, including activated oncogenes and inactivated tumor suppressor genes. In addition to abnormal cell proliferation, cells must acquire several other traits for tumor progression to occur. For example, early on in tumor progression, cells must evade the host immune system. Further, as tumor mass increases, the tumor must acquire vasculature to supply nourishment and remove metabolic waste. Additionally, cells must acquire an ability to invade adjacent tissue. In many cases, cells ultimately acquire the capacity to metastasize to distant sites.
It is apparent that the complex process of tumor development and growth must involve multiple gene products. It is therefore important to define the role of specific genes involved in tumor development and growth, and to identify those genes and gene products that can serve as targets for the diagnosis, prevention and treatment of cancers.
Once it is known that a patient has cancer, it then becomes necessary to determine which method of treatment the patient will most benefit from. Part of this determination involves assessing which type of cancer the patient suffers from, which genes are involved in causing the cancer, and which tissue is specifically affected. There is a need in the art for methods to determine the appropriate treatment for subjects with cancer.